Devices for control of a gear box



April 3, 1962 J. H. A. CLAUDON 3,027,777

DEVICES FOR CONTROL OF A GEAR BOX Filed Dec. 4, 1959 2 Sheets-Sheet 1 ARPMI IIIHN /ean f/eMz'A /Bfne (400V 7 5;.- 7. Ajay-4 April 3, 1962 J. H. A. CLAUDON 3,027,777

DEVICES FOR CONTROL OF A GEAR BOX 2 Sheets-Sheet 2 Filed Dec. 4, 1959 m 3 m2 a MF: 9& h I/eArIAIIIB I AE D United States Patent 3,027,777 DEVICES FOR CONTROL OF A GEAR BOX Jean Henri Antoine Claudon, Clos-Jean, Pont-a-Mousson, France, assignor to Compagnie de Pont-a-Mousson, Nancy, France, a body corporate of France Filed Dec. 4, 1959, Ser. No. 857,342 Claims priority, application France Dec. 9, 1958 12 Claims. (Cl. 74-472) This invention relates to an improved device for the control of a gear box having epicyclic trains in constant mesh and being driven by a driving shaft and being actuated by means of a liquid under pressure, particularly oil, to put in play selectively the trains according to the speed to be reached by the automotive vehicle.

This device is of the well known type in which a source of liquid under pressure is connected to the actuating means by means of a speed selector, operated by a pilot device.

As a feature of this invention, the selector comprises a movable part forming a double-acting piston and is connected on both sides of said piston with the pilot device, which is located above the selector and is combined with a container for liquid under pressure and with electrical control means to put in communication one of the faces of said piston either with the exhaust or with said container in order to obtain the step-by-step displacements of said movable part of the selector.

As a result of this feature, the construction of the device is very simplified; a very simple operation of the selector is obtained, since the liquid admitted therein at each change of speed cannot escape therefrom, between two changes of speed, because the selector is located below the pilot device, and this notwithstanding the fact that the face of the piston which has received the liquid during the preceding change is now on the exhaust phase.

According to another feature, the electrical control means of the pilot device comprise two electromagnets, adapted to move in opposite directions the movable part of said pilot device for the increase or the decrease of the speeds; the feed circuits for these electro-magnets comprise two intensity-relay contact-makers the windings of which are connected in parallel with said electro-magnets to one of the terminals of an electric source, while in order to permit their selective feeding they are connected to the other terminal, on the one hand by a manual inverser, and on the other hand by a pair of circuit-breakers mounted in parallel and combined with a centrifuge regulator mounted on the driving shaft in such manner that one of said interruptors or circuit-breakers is closed for the rise of the speeds for a high load of the motor and the other for the decrease of the speeds for a low load of said motor.

This invention relates also to a transmission system comprising in combination a motor, a speed box provided with actuating means actuated by a compressed fluid for the change of speeds and an improved device of automatic control of the type described above.

Other features and advantages of this invention will appear from the following description.

' In the attached drawing, given solely by way of illustration:

FIG. 1 shows diagrammatically a transmission system according to this invention, in position of first speed;

FIG. 2 is an enlarged transverse cross section of the speed selector taken along line 22 of FIG. 1;

FIG. 3 is a partial horizontal cross-section of the selector taken along line 33 of FIG. 2;

FIG. 4 illustrates diagrammatically a detail of control of the electric part of the control device by means of the accelerating pedal of the vehicle;

3,027,777 Patented Apr. 3, 1962 ice FIG. 5 illustrates diagrammatically another detail of control of the electric part of the control device for the selection of the manual, semi-automatic or automatic, control of the hydraulic part of said device.

According to the illustrated form of the device, the invention is applied to the control of a speed box A. This box A permits variations in the transmission ratios between a driving shaft B, located at the outlet of motor M, and a driven shaft C, in function of the speed of the driving shaft B by means of a centrifuge regulator R mounted on said driving shaft.

Box A is of any of the well-known types having epicyclic trains and will therefore not be represented in detail. -It permits, for instance, to obtain four forward speeds, the fourth one being overmultiplied, and a rearward speed, each of these speeds being engaged by the admission of oil under constant pressure, respectively in an actuating jack V V V V, or VR each insuring, as well known per se, the engagement of one of the speeds, therefore a given transmission ratio between shafts B and C.

The oil under pressure is supplied by a pump D operated by driving shaft B. Pump D discharges in a pipe 1 on which is mounted in derivation a valve box E having a ball 2 and a spring 3 and opening at 4 into the discharge; spring 3 is so calibrated that the valve box opens for a maximum pressure P of the order of 18 kg./ 0111. for instance.

Two other pipes 5 and 6 are connected in derivation to pipe 1.

Pipe '5 is connected to one of the ways of a three-way valve F, the two other ways of which are formed by a discharge orifice 7 and by a conduit 8 leading to a speed selector S, the function of which is to distribute the oil under pressure to one of the jacks V V V V and VR.

Valve F comprises a slide 9 adapted to occupy one or the other of two positions, in which conduit 8 is connected to pipe 5 or to discharge 7, under the opposed actions, respectively, of a spring 10 and of an electro-magnet 11. The winding of the latter is connected on the one hand to the positive terminal a of the battery 12 of the vehicle and, on the other hand, to the mass b by means of an interruptor I The latter cooperates with a. finger 13 combined with the slide 14 of a second centrifuge regulator R which is so regulated that interruptor I is closed as soon as motor 'M exceeds the slow-down speed, of the order of 500 revolutions per minute for instance; this then puts the slide 9 in position of discharge, while pipes 7 and 8 are automatically put into communication as soon as the speed of the motor exceeds the foregoing value.

Furthermore, pipe 6 is also connected to two other pipes 15 and 16; pipe 15 leads to the speed selector S, while pipe 16 leads to a pilot device P, the purport of which is to control automatically selector S for the changes of speed from neutral to fourth speed (increase) and from the fourth to the second speed (decrease).

A check valve 17 is mounted on pipe 15; its purpose is to maintain in pipes 1, 5, 6, 15 and 16 a given residual pressure p lower than P and, for instance, at least equal to 12 lag/cm. when the jacks V V V V and VR are on discharge.

For a purpose explained later, selector S is located at the lowermost portion of the whole of the device and, in any event, below the pilot device P, FIG. 1 corresponding to a diagrammatical partial cross-section of the assembled device.

Selector S comprises an elongated body 18, pierced longitudinally and all through with a bore 19 within which is set a tubular element 20, the length of which is shorter than that of said bore, and which forms a. second bore 21, coaxial with bore 19 and closed at its left end (as shown in FIG. 1).

The housing formed by the bore 19 is closed at one of its ends by a threaded plug 22, and its other end by tubular element 20.

Body 18, in which check valve 17 is mounted, comprises a bored extension 15a of pipe 15.

tlnto bore 19 of body 18, and respectively near the end of tubular element 20 and near plug 22, there are two conduits 23 and 24 opening into said bore, and serving as connections with the pilot device P. On the other hand, there are, opening into bore 21 of tubular element 20 by means of radial orifices disposed to coincide in body 18 and in tubular element 20, six conduits 25, 26, 27, 28, 29 and 30, respectively connected to the jacks V V V V and VR and to the discharge.

\Further tubular element 20 comprises two bored portions, one which accommodates at its end conduit 8 which, thus, opens into the end of bore 21, and the other one, a discharge conduit 31, which opens at a distance from the bottom of bore 21 equal to the distance between conduits 25 and 28, relating respectively to the first and the fourth speeds. Finally, tubular element 20 is pierced with a longitudinal groove 32, the length of which corresponds to the distance between conduits 28 and 29, relating respectively to the fourth speed and to the backward operation.

A slide 33 slides in the bore 21 of tubular element 20. Slide 33 comprises a circular groove 34 adapted to place in communication one of the five conduits 25 to 29 with the conduit (15, 15a) through which the oil under pressure is fed. Slide 33 also comprises two longitudinal grooves 35 and 36, facing conduits 25 to 30, and connected together by an internal conduit 37. The length of groove 35 corresponds to the distance between the forward run conduits 25 and 28, increased by the distance between two consecutive conduits of the set of conduits 25 to 28. As to groove 36, its length corresponds to the distance between the conduits 27 (third speed) and 30 (discharge) In bore 21, the end of slide 33 facing conduit 8 acts as a single-effect piston-ring. This slide extends beyond tubular element 20 and slides in the bore 19 of body 18 by means of a collar 38 acting as a double-effect piston and separating in a fluid-tight manner conduits 23 and 24 which open into the two annular chambers K and L provided within bore 19 on both sides of said collar. Moreover, slide 33 which goes through threaded plug 22 comprises an axial cylindrical cavity 39 which is connected:

On the one hand, with the outside through a hole 40 of an end piece 41 keyed at 42 to the right end of the slide (as shown in FIG. 1);

And on the other hand, for given positions of said slide, with bore 19 through an orifice 43.

Moreover, slide 33 comprises, 011 the side of plug 22:

Six notches 44 (FIGS. 1, 2) corresponding from left to right to the six successive positions of backward run (AR), neutral point (PM) first (I), second (II), third (III) and fourth (IV) speeds, these notches cooperating with a locking device mounted in plug 22 and comprising a ball 45 adapted to engage any one of said notches under the action of a spring 46;

Three notches 47 facing the notches 44 of the second (II), third (III) and fourth (IV) speeds (FIGS. 1 and 2) and a groove 48 facing the notches of first speed (I), neutral PM and of backing (AR); these notches 47 and the groove 48 cooperate with a ball 49 subjected to the thrust of a spring 50 to control an electric contactor C (FIGS. 1 and 2) feeding a relay of temporization RT (FIG. 1), said contactor being closed when said ball is disengaged from any of the notches 47 or from the groove 48;

Another groove 51 (FIGS. 2, 3) located at right angle to the notches 44 of first (I) to third (III) speeds, this groove cooperating with a ball 52 pushed by a spring 53 to close a contactor C when the ball enters the groove;

A third groove 54 located at right angle to the notches 4.- 44 of second (II), third (III) and fourth (IV) speeds, this groove cooperating with a ball 55 pushed by a spring 56 to close a third contactor C when the ball enters the groove (FIGS. 2, 3).

Finally, the right end (FIG. 1) of slide 33 is connected by means of end piece 41 with an operating handle 57.

The pilot device P comprises a body 58 having a bore 59, 60, the diameter of bore 60 being greater than that of bore 59. The smaller diameter part 59 is closed by a threaded plug 61, while the larger bore 60 comprises at its left end (FIG. 1) a tubular socket 62, threaded and forming a stop. Body 58 is pierced radially by pipe 16 and by the conduits 23 and 24 for automatic operation of the selector in both directions; these conduits 23 and 24 open into the stage 59 of the bore, just as do two discharge orifices 63 and 64 located respectively on both sides of said conduits 23 and 24 and a conduit 65 connected to a bottle G containing oil under pressure. In the two stages 59 and 60 of the bore a slide 66 is adapted to move longitudinally. This slide 66 is provided:

First, with two broad circular recesses 67 and 68 separated by collars and adapted to connect respectively the conduits 23 and 24 either with the discharge orifices 63 and 64, or with the feed conduit 65 for oil under pressure coming from bottle G;

Second, with two narrow circular grooves 69 and 70 communicating together through an internal conduit 71 and adapted to connect conduit 16 with conduit 65 in order to feed bottle G.

Slide 66 is extended:

On the one hand, at its left (FIG. 1) with a rod 72 which has at its end a flange 73, and on which can slide two washers 74 and 75, separated by a spring 76 which tends to apply washer '74 against the shoulder between stages 59 and 60 of the bore and washer 75 against flange 73 and stop socket 62;

And, on the other hand, on its right, by an operating rod 77, ending with a soft iron core 78, adapted to be attracted either by an electro-magnet 79 for the increase of the speeds, or by an electromagnet for the decrease.

Therefore, slide 66 can move in two opposite directions under the action of one or of the other of said electro-magnets and against spring 76 abutting in one direction washer 74, temporarily stationary, and, in the other direction washer 75, in turn temporarily stationary.

Thus, slide 66 can occupy three positions:

First, a median position shown in FIG. 1, which corresponds to the stage when electro-magnets 79 and 80 are not excited, and in which the conduits 23 and 24 are simultaneously connected to the discharge orifices 63 and 64, while conduit 16 is connected with conduit 65 to feed bottle G;

And, second, two extreme positions toward the left and the right, which correspond to the excitation respectively of electro-magnet 79 or 80, and in which one of conduits 24 or 23 is connected with conduit 65, while the other is connected with the discharge orifices 63 or 64, conduit 16 being then separated from conduit 65 by the collar separating grooves 67 and 70.

A piston 81 moves in bottle G; this piston is subjected to the opposed pushes of the pressure of the oil fed by conduit 65 and of a spring 81a.

The electric control device, combined with the hydraulic device above, will now be described.

are connected, on the one hand, in parallel to conductor 82 and, on the other hand, on a circuit of low intensity to two conductors 85 and 86 corresponding respectively to the increase and the decrease of the speeds. The excitation of either electro-magnets 79 or 80 by contactors MC or DC can be controlled at will by means of one or the other of two control electric devices, one being semi-automatic and the other automatic, connected in parallel to conductors 85 and 86.

The last mentioned semi-automatic control device comprises two conductors 87 and 88 connected selectively to the mass b by a manual reverser 89, adapted to rotate, in the direction of arrow m, to feed electro-magnet 79 for increasing speeds and, in the direction of arrow d, to feed electro-magnet 80 for decreasing speeds.

The last mentioned automatic control device comprises two conductors 90 and 91 onto which are mounted in series respectively contactors C and C operated by the slide 33 of selector S, and which are selectively connected to a ground conduit 92 by the closure of one of the two intcrruptors I and I These two interruptors are combined with an actuating finger 93 integral with sliding collar 94' of the centrifuge regulator R shown diagrammatically (FIG. 1) for a better understanding, and the control is such that said finger closes interruptors I and I respectively for a low load of the motor, for instance beginning at 1200 revolutions per minute, and for a high load of the motor, for instance beginning at 4000 revolu tions per minute. and 1 are also subjected to the action of an opposing spring, not shown, which reopens the circuit and breaks the feed of electric current as soon as finger 93 ceases to exert pressure.

It is to be noted that interruptors I There are connected in derivation to conductors 90 I and 91 conductors 94 and 95, connected to the ground conduit 92 through interruptors I and 1,, respectively, which are to be closed under the pressure of finger 93 for intermediate motor loads of 2000 revolutions per minute and 3000 revolutions per minute respectively, for instance.

Moreover, auxiliary contactors C and C are respectively mounted in series on conductors 94 and 95; these auxiliary contactors are normally open and correspond respectively to the control of the speeds increase and to that of the speeds decrease.

Auxiliary contactors C and C are controlled by the acceleration pedal 96 of the vehicle (FIG. 4). Contactor C is closed when the pedal is released to position 96a and contactor C is closed when accelerator 96 is in full operating position as shown at 96b.

On the other hand, between the high intensity conductor 82 and the ground conduit 92, there is mounted in parallel with these parts a relay of temporization RT, the winding of which is in series with contactor C placed under the control of slide 33 of selector S (FIGS. 1 and 2). This relay RT controls a contactor RTC through which the ground conduit 92 is connected to the mass at b.

Relay RT is such that contactor RTC is usually closed and is open, with a certain delay and during a time sufficient to enable source D to fill bottle G, when relay RT is excited. The delay in the opening of contactor RTC after excitation of relay RT corresponds to the time required to pass from one speed to the next one, automatically, between neutral point and the fourth speed; and this relay may be, for instance, capable of maintaining contactor RTC open for two seconds after change of one speed.

An automatic electric control contactor 97 is mounted in series with contactor RTC on the ground conduit 92.

Contactors 83 and 97 are placed (FIG. 5) by means of balls 98, 99 and of springs 100, 101 under the control 6 of a cam-rod 102 operated by hand and adapted to occupy three positions:

The first (M for manual operation, in which the two contactors 8'3, 97 are open simultaneously, when the balls engage a recess 103 of earn 102; the electric control cannot function;

The second (S,,) for which contactor 83 alone is closed by the disengagement of the corresponding ball 98 out of the recess 103 of earn 102; the semiautomatic electric control by reverser 89 can then operate, while the automatic control by regulator R remains stopped;

The third (A) for which both contactors 83 and 97 are simultaneously closed by the disengagement of balls 98, 99 out of the recess 103 of cam 102; both the semiautomatic and the automatic electric controls can function.

OPERATION The operation of the hydraulic system will be described first, that of the electric system afterwards.

(I) Hydraulic System The vehicle being stopped, the motor stopped and slide 33 of selector S at dead point, there is no pressure of oil in the conduits since pump D does not: deliver. When motor M is started, it rotates first at slow speeds of about 500 revolutions per minute. Slide '33 of selector S is moved by hand from the neutral point (PM) to first speed (I) by means of rod 57, in such a way as to connect the conduit 15, 15a with the conduit 25 for jack V (as shown in FIG. 1). Thereafter the motor is accelerated in order to exceed the slow speed of about 500 rpm. and to reach, for instance the speed of 1500 r.p.rn.; pump D starts to discharge into conduits 1, 5, 6, 15 and 16 and up to selector S, jack VI and pilot P under a pressure which may rise, for instance, to a value of the order of 15 kg./cm. Then the vehicle starts. Simultaneously, as soon as the operation at slow speeds is exceeded, the finger 13 of regulator R closes interruptor I Electromagnet 11, which is then excited, attracts slide 9 of valve F against the action of spring 10. The feed conduit 5 for the oil under pressure is then closed, while conduit 8 is connected with discharge orifice 7.

Slide 66 of pilot system P being in median position (FIG. 1), conduits 16 and 65 communicate and the oil fills bottle G until spring 81a is completely retracted. The pilot system is then in measure to cause the operation of selector S for the rise of speeds from first to fourth.

(A) INCREASE OF THE SPEEDS FROM FIRST TO FOURTH Electro-magnet 79 is subjected to an instantaneous excitation, either by hand with the help of reverser 89 moved in the direction of arrow m and then returned to its median rest position, or automatically as will be described hereafter. Slide 66 of the pilot device is drawn toward the flange 75 and the socket 62, compressing spring 76, and takes its most leftward position. The discharge orifice 64 is then closed While the empty conduit 24 is placed in communication with conduit 65, which is filled with oil under a pressure of 15 kg./cm. Under the pressure of spring 81a, the piston 81 of bottle G sends the oil in conduit 24 and into chamber L located between the collar-piston 38 of slide 33 of the selector and the plug 22. Then the oil exerts a push leftward upon piston 38 until it fills said chamber L until its volume corresponds to that of bottle G and to the displacement of the slide of the selector from a notch of first speed (I) into second speed (II). The excitation of electro-magnet 79 being merely momentaneous the slide 66 of pilot P is returned to median position by spring 76, whereby the empty bottle G can be filled again. Although conduit 24 is again connected to the discharge orifice 64, cham ber L of bore 19 of selector S, comprised between piston 38 and plug 22, remains full of oil under the same volume, as a result of the low location of selector S which does not allow the oil to flow upward through conduit 24 nor to empty through orifice 64.

When electro-magnet 79 is again excited, the same process is reproduced. Because the oil is not compressible, the volume of chamber L increases by a quantity corresponding to the volume of bottle G and causes again the displacement of the slide of the selector by one notch. The third speed (III) is engaged. The automatic passage to fourth speed is effected in the same way.

(B) DECREASE OF THE SPEEDS When the slide 33 of selector 8 is in first or second speed, the chamber K provided in bore 19 of selector S, between piston 38 and tubular element 20, is, irrespective of the position of slid-e 66 of the pilot device P, in communication with cavity 39 of slide 33 through orifice 43, and therefore set for discharge at 40. Therefore it is impossible to exert a hydraulic push on the left face of piston 38 toward plug 22. The result is that it is impos- H sible to go back with the help of pilot device P from sec ond speed to neutral. Orifice 43 is thus a safety aiming to prevent the return to first speed for an excessive operation of the motor and for too fast a speed of the vehicle, which would be dangerous.

Therefore, the slide 33 of selector S will be assumed to be in third or fourth speed. In one of these positions, exhaust orifice 43 is closed by tubular element 20. The electro-magnet 80 being excited temporarily either by the operation of reverser 89 or, automatically, slide 66 of pilot device P is drawn toward plug 61. The conduit 24 is then connected to discharge 64, while conduit 23 is connected to conduit 65; therefore bottle G empties into the chamber K of bore 19 of selector S, formed between piston 38 and tubular element 20. Thus, the oil, under a pressure of about 15 kg./cm. moves, by means of collar-piston 38, the slide 33 towards plug 22 until said chamber is filled with a quantity of oil corresponding to the volume of bottle G, while chamber L, formed between piston 38 and plug 22, empties by the same amount through conduit 24 and discharge orifice 64. Slide 33, then, is moved one notch to the right. The lower speed (second or third) is then engaged. Electro-magnet 80 is no longer excited and slide 66 returns to median position under the action of spring 76.

(C) AUTOMATIC RETURN TO FIRST SPEED FOR A SLO\V RUNNING OF THE MOTOR When the running speed of the motor decreases and falls to throttled down speed, the movable finger 13 of centrifuge regulator R moves to the left and ceases to bear on interruptor I which opens. Electromagnet 11 not being any longer excited, slide 9 of valve F is moved to the right by spring 10 and places in communication the feed conduit for the oil under pressure and the conduit 8 opening at the end of bore 21 of selector S. The oil admitted into said bore 21 then moves slide 33 toward the right until it is locked in first speed; the slide cannot be moved further to neutral or to rear motion, because from the moment it is in first speed, a new move to the right would unmask the discharge orifice 31, through which the oil coming from conduit 8 would escape.

(H) Electric System (1) SEMLAUTOMATIC CONTROL BY MEANS OF REVERSER 89 Interruptor 83 being closed, the current can pass through one of the two circuits 85, 87 or 86, 88 into one of the electro-rnagnets 79 or 80 when manual reverser 89 is placed in one or the other of its extreme positions and thereby causes the feeding of one of the relays RM or RD and the closing of one of the contactors MC, DC. On the other haind, when reverser 89 is at its intermediate position, contactors MC and DC remain open and no current can flow into electromagnets 79 and 80. Be-

cause of the relays of intensity RC and RD, the reverser 89, by measure of safety, controls only a current of weak intensity, while a current of high intensity is required to operate the electro-magnets.

(2) AUTOMATIC CONTROL BY MEANS OF CENTRIFUGE REGULATOR R1 The interruptors 83 and 97 being closed by the operation of cam .102, the current can flow into the ground-return conductor 92 as well as into automatic control conductors 90 and 91. Under these conditions:

(a Increase of the speeds.-When slide 33 of the selector is at neutral or dead point and when the motor is throttled to slow speed (500 revolutions per minute), finger 13 of centrifuge regulator R is in the position shown in FIG. 1. \All the interruptors I I I 1.; are open as well as contactor C No current flows through conductors 90, 91 and 92, nor, therefore, into electromagnets 79 and 80.

Slide 33 of selector S being moved by hand from the neutral point to first speed, it will be assumed that the motor has been accelerated up to 4000 revolutions per minute. The vehicle moves. Simultaneously, upon the change of motor speed to slow speed, finger 93 of regulator R moves toward the right, closing successively interruptors I I and L; which open again after the passage of said finger, then maintaining interruptor I closed (which corresponds to 4000 r.p.m.). It is to be noted that the closing of interruptors I and 1., would be ineffectual, since contactor C controlled by slide 33 of selector S is open at first speed as shown in FIG. 3. The closing of interruptor I is also inelfectual because the contactor C controlled by the pedal of acceleration 96,

pushed forward into 96b, is open (FIG. 4). On the other hand, contactor C controlled by the slide 33 of selector 5, being closed at first speed (FIG. 3), the closing of interruptor I permits electro-rnagnet 79 to be excited for increases of speed. The hydraulic system described above then operates and the second speed is engaged. The high operating state of the motor at 4000 r.p.m. at least being maintained by the forward push of pedal 96 to allow the vehicle to increase speed, finger 93 of regullator R maintains the interruptor I closed. However, when passing from first to second speed, the operation .of the relay RT, controlled by slide 33 of selector S, has been started as a result of the disengagement of ball 49 from the notch 47 for first speed (FIG. 1). Therefore, when said slide has just been released from second speed, relay RT causes the opening of contactor RTC during 2 seconds, for instance. During that time of opening, the electric circuit 90, 91 controlling electro-magnet 79 is no longer fed; slide '66 of pilot device P returns to its median position, which allows for the filling of empty bottle G. When the action of relay RT stops, contactor RTC closes again, which causes again the excitation of electro-magnet 7 9 and promotes another automatic passage to the higher speed. The second and the third speeds corresponding to direct coupling are thus automatically engaged without intervention of the driver, simply as a result of the increase of speed of the motor.

When slide 33 is locked in third speed, contactor C which it controls (FIG. 3) opens as a result of the disengagement of ball 52 coacting with groove 51. The

current can no longer pass through conductors 90 and (b Decrease of the speeds-It will now be assumed that the operation of the motor decreases from 4000 to 3000 r.p.m., without release by the driver of his pressure on pedal 96, for instance because motor M must support an important effort, particularlry on a hill. Finger 93 of regulator R moves from interruptor 1 toward interruptor 1 which it closes. Since contactor C is also closed because of the pushing of pedal 96 into 96b (FIG. 4), the current flows into conductors 91 and 92. Relay RD is fed, which causes the closing of contactor DC and the excitation of speed-decrease electro-magnet 80. The operation of the hydraulic system to pass from fourth to third speed proceeds as previously described. When it moves, slide 33 of selector S liberates from the fourth speed notch 47 the ball 49 of the contactor C of relay RT; this causes, from the moment when slide 33 is locked in third speed, the opening of circuits 90, 91 and 92 for two seconds, as a result of the opening of contactor RTC. The result is that the following change of speed, either for the increase or for the decrease, cannot occur before about two seconds, which is a sufiicient time for refilling bottle G.

If the operation of the motor continues to decrease down to 2000 r.p.m., the pedal 96 remaining pushed down to give to the motor the maximum of power, interruptor I is now closed by finger 93. However, this is without result, because contactor C controlled by pedal 96 (FIG. 4) is open. The motors operation continuing to decrease down to 1200 r.p.m., pedal 96 remaining pushed down, finger 93 moves and closes interruptor 1 which causes the feeding of relay RD because of the closing of contactor C the ball 55 of which is engaged in groove 54 (FIG. 2).

The operation of the electric and hydraulic systems proceeds as heretofore. The selector passes from third to second speed without intervention of the driver.

If the motor continues to operate at 1200 r.p.m., interrupter 1 remains closed but in second speed contactor C is opened by the slide of the selector (FIG. 3). Therefore electro-magnet 80 cannot be excited and the automatic passage from second to first speed, for the stated operating speed of the motor, is impossible. It has been seen above that the decrease from second to first speed would also be impossible, hydraulically, because of the existence of discharge orifice 43 in slide 33 of the selector. This, then, provides for a safety in the event that contactor C would not open in second speed.

In short, the automatic or semi-automatic electric control allows to change speeds from first to fourth on the increase and from fourth to second for the decrease.

If the operating speed of the motor continues to decrease down to 500 r.p.m., it is the regulator R which causes automatically the return to first speed, as described heretofore.

Because of conductors 94 and 95, of interruptors I and I and of contactors C and C the changes of speeds can be controlled by the driver by its sole action on accelerating pedal 9-6 between 1200 and 4000 rpm. If, for operating speed of the motor of 3000 r.p.m., pedal 96 is released into position 96a, when the speed of the vehicle increases because the action of the weight is added to that of the motor, contactor C is open. The passage to the lower transmission ratio is not advantageous in that case and is impossible. On the other hand, contactor C is closed and if, under the same conditions, the motors speed decreases down to 2000 r.p.m., the action of the weight being suflicient to move the vehicle, the change to the upper transmission ratio, which is advantageous, occurs. Similarly, when starting on a down slope, it is not necessary to reach the motors speed of 4000 r.p.m. to cause the change to the upper speeds. The accelerator being released, from 2000 r.p.m., the increase of speeds occurs. Therefore, because of this system, the ratio of engaged transmission is always suited to the driving conditions of the Vehicle, without special intervention by the driver. It is the only action of the latter on pedal 96 which conditions either the decrease of the speeds when the torque of resistance increases or the change to higher speeds when the torque of resistance decreases. Besides the fact that the driving is pleasant for the driver, no jamming of the motor is possible because the motor never has to supply an excessive torque, and the running of the vehicle without killing it can be very economical by means of the judicious use of the weight to contribute to the entrainment of the vehicle. It is to be noted that, even when the automatic electric control is engaged, the manual hydraulic control directly through the operation of rod 57 of selector S and the semi-automatic electric control through reverser 89 are still possible.

On the other hand, the vehicles safe driving is due to contactors C and C and to the corresponding grooves 51 and 5'4 of slide 33. In fact, the passage to the overmultiplied speed, which must be efli ected carefully taking in consideration the conditions of the road trafiic, and not only in function of the resisting torque, is left to the sole discretion of the driver, as a result of contactor C The same is true for the change from neutral to first speed. The contactor 0;, makes a brutal jolt, by automatic change from second to first speed when the motors operating speed is too high (1200 r.p.m.) and when the vehicles speed is still important, impossible.

Another driving safety is due to regulator R valve F and conduit 8 which allow to benefit quickly by the motor brake in first speed, engaged automatically for a slow enough operating speed of the motor, eventually directly from fourth to first speed upon braking, without waiting for the few seconds required for the electric control to effect, step by step, the decrease of the speeds. It should be understood that a sharp break in the motors operating speed is involved.

This invention is not limited to the embodiment described and illustrated, which has been selected merely for an example. Thus, the control device described above for a gear box with four forward speeds can also be adapted to a box with five forward speeds, the fifth one being overmultiplied. This control device can also be adapted to a gear box having no overmultiplied forward speed. In that case, the groove 51 of slide 33 of the selector extends from the notch of the first speed to the notch for the direct engagement of the speed.

Also, a single centrifuge regulator on driving shaft B can be so disposed as to act simultaneously on the electric control of electro-magnets 79 and 80 and of valve F.

Having now described my invention what I claim as new and desire to secure by Letters Patent is:

l. A control device for a gear box driven by a driving shaft and provided with actuating devices operated by a liquid under pressure, said device comprising in combination: a source of liquid under pressure; a selector of speeds for connecting selectively and individually said source to each of said actuating devices; said selector having a first inner slide, one end of which forms a single acting piston; on said slide, a collar forming a double-acting piston; a pilot device adapted to actuate said selector, located above the latter and provided with a second inner slide; a bottle of liquid under pressure having an injection piston and adapted to be entirely filled and emptied; fluid conduits connecting directly said source of liquid with the selector and also connecting directly said selector to said actuating devices; a separate fiuid conduit connecting said source of liquid with said pilot device; a fluid injection conduit connecting said bottle of liquid with said pilot device; two additional fluid injection conduits connecting said pilot device with said selector and opening into the inside of said selector on opposite sides of said double-acting piston, one of said injection conduits relating to the increases of speeds, and the second of said injection conduits relating to the decreases of speeds; on said pilot device, two fluid discharge conduits close to said additional fluid injection conduits, each of said discharge conduits being adapted to be put in communication with one of said additional injection conduits and to be separated from the latter by means of said second slide in said pilot device; an electric control device for moving longitudinally said second slide of said pilot device selectively in both directions, in such a manner that each of the faces of said double-acting piston is alternatively connected with said bottle, in order to insure a step-by-step displacement of said double-acting piston and, consequently, a step-by-step change of speeds other than the change from second speed to first speed; each step of speeds corresponding to the connection of said source of liquid with one of said actuating devices through said selector; and, between said source of liquid and said selector, a valve device and a further fluid conduit opening into said selector in front of said single-acting piston for controlling the change of speeds from second speed to first speed under the control of said valve device; the latter and said further fluid conduit being disposed in series.

2. A control device as claimed in claim 1, in which said selector comprises a body having a bore, said doubleacting piston being movable longitudinally in a portion of said bore and forming in said bore on one of its sides a first chamber and on the other one of its sides a second chamber; said first chamber being used for increases in speeds and said second chamber for decreases in speeds; said device comprising further connections between said chambers and said pilot device wherethrough one of said chambers, according to the direction of the change of speeds, is connected alternately with said bottle and with said discharge means.

3. A control device as claimed in claim 1, comprising further a transmission group between a motor and a driven shaft, said group comprising said driving shaft driven by said motor; said gear box driving said driven shaft; said gear box being of the epicyclic type, and said actuating devices being operated by means of oil under pressure for changing gears and speeds.

4. A control device according to claim 1, in which said selector comprises a body having a bore, said doubleacting piston being movable longitudinally in a portion of said bore; and in which, in said bore, a first chamber is formed on one side of said piston and a second chamber is formed on the other side of said piston, the first chamber being used for increases in speeds and the second chamber for decreases in speeds, fluid conduits of connection between said chambers and said pilot device Wherethrough one of said chambers, according to the direction of the change of speed, is connected alternately with said bottle and with said discharge means; said movable part of said selector being pierced with a discharge channel; said discharge means comprising a dis charge orifice; said discharge channel opening through said discharge orifice into said second chamber for the decreases in speeds; said selector comprising further a fixed tubular closure in which the end of said movable slide of said selector forming a single-acting piston slides, said closure being adapted to close said discharge orifice when said slide is in any position other than those corresponding to reverse, neutral and first speed.

5. A control device according to claim 1, in which said valve device is interposed between said source of liquid under pressure and said selector, on the fluid conduit opening at the end of said selector in front of said singleacting piston; said valve device comprising an other slide for putting said last named fluid conduit in communication with, and separating it, from, a discharge orifice, and, to act in opposition on said other slide, a spring and an electro-magnet; the feed circuit of said electro-magnet comprising an interruptor combined with a centrifuge regulator mounted on said driving shaft and set in such a manner that said single-acting piston is returned from the position of second speed to that of first speed only when the speed of said driving shaft corresponds to low speed.

6. A control device according to claim 1, in which said pilot device comprises a cylinder connected With the body of said selector by means of two first conduits opening respectively into the opposite ends of said first and second chambers and into the discharge through two other conduits respectively adjacent to one of said first conduits, and into said bottle through a fifth conduit, said slide of said pilot device comprising two circumferential grooves so disposed that when one of said first conduits is connected with the corresponding one of said first and second chambers the corresponding discharge conduit is closed, while the other one of said first conduits communicates with the other one of said corresponding discharge conduits.

7. A control device as claimed in claim 1, comprising further an inner slide in said pilot device and elastic device in said pilot device, said slide abutting in both directions upon said elastic device for return to a median longitudinal position in said pilot device.

8. A control device as claimed in claim 1, in which said electric control device comprises: two electro-magnets adapted to move the slide of said pilot device in opposite directions for the increase and the decrease of the speeds; feed circuits for said electro-magnets comprising two contactors with intensity relays; a source of electric current; the windings of said relays being connected in parallel with said electromagnets to one of the terminals of said source of current, while in order to allow their selective feeding they are connected to the other terminal of said source of current on the one hand by a manual reverser and, on the other hand, by a pair of interruptors themselves in parallel and combined with a centrifuge regulator mounted on the driving shaft in such a manner that one of said interruptors is closed for the increase of the speeds during a high operating speed of said driving shaft, and the other is closed for the decrease of the speeds during a low operating speed of said shaft.

9? A control device according to claim 8, in which the windings of said relays for the increase and for the decrease are connected directly to said reverser and indirectly to said interruptors through a contactor of increase and a contactor of decrease, the closing of the feed circuit of said relays, which passes through said contactors and said interruptors in parallel, being effected through a third contactor normally closed, and actuated in the direction of its opening by a delaying relay itself fed through a fourth contactor, whereby said circuit is opened with a delay in its excitation corresponding to the time required for the automatic change of speeds, one by one, and during a time sufiicient to fill said bottle.

10. A control device according to claim 9, in which said slide of said selector comprises an extension, said fourth contactor and said contactors of increase and of decrease being placed around said extension and being provided with operating pushes maintained in resilient contact with said extension, the latter being provided with notches and grooves adapted to operate said three contactors in function of the positions of said slide of said selector, said notches and grooves being so arranged that the said contactor of said delaying relay is closed upon each change of speed and open when the speeds are engaged, while the contactor of increase is closed from the first speed to the speed next below the last highest speed and the contactor of decrease is closed for the second and higher speeds.

11. The combination of a transmission assembly consisting of a motor, a first shaft driven by said motor, a gear boX driven by said shaft and driven shaft connected to said gear box, the latter being of the epicyclic type and provided with acuating devices operated under consant pressure by oil, for changing gears and speeds; accelerating means for said motor, and of a control device for said gear box, said device comprising in combination: a source of liquid under pressure; a selector of speeds for connecting selectively and individually said source to each of said actuating devices; said selector having a first inner slide, one end of which forms a single-acting piston; on said slide, a collar forming a double-acting piston; a pilot device adapted to actuate said selector, located above the latter and provided with a second inner slide; a bottle of liquid under pressure having an injection piston and adapted to be entirely filled and emptied; fluid conduits connecting directly said sources of liquid with said selector and also connecting directly said selector with said actuating devices; a separate fluid conduit connecting said source of liquid with said pilot device; a fluid injection conduit connecting said bottle of liquid with said pilot device; two additional fluid injection conduits connecting said pilot device with said selector and opening into said selector on opposite sides of said doubleacting piston, one of said injection conduits relating to the increases of speeds, and the second of said injection conduits relating to the decreases of speeds; on said pilot device, two fluid discharge conduits close to said additional fluid injection conduits, each of said discharge conduits being adapted to be put in communication with one of said additional injection conduits and to be separated from the latter by means of the slide of the pilot device; an electric control device adapted to connect alternately one of the faces of said double piston with said discharge conduits and with said bottle to produce a step-by-step displacement of said slide of the selector; in said electric control device, two electro-magnets; said two electromagnets being adapted to move said slide of said pilot device in opposite directions respectively for the increase and the decrease of the speeds; in the feed circuit for said two electro-magnets, two contactors with intensity relays having windings; a source of electric current; said windings being connected in parallel with said electromagnets to one of the terminals of said source of current, while in order to allow their selective feeding, said windings are connected to the other terminal of said source of current by a manual reverser and by two interruptors themselves in parallel and combined with a centrifuge regulator mounted on the driving shaft in such a manner that one of said interruptors is closed for the increase of the speeds during a high operating speed of said driving shaft, and the other interruptor is closed for the decrease of the speeds during a low operating speed of said shaft; the windings of said relays, one for the increase and the other for the decrease being connected directly to said reverser and indirectly to said interruptors through a first contactor of increase and a second contactor of decrease; the closing of the feed circuit of said relays, said circuit passing through said contactors and interruptors in parallel, being effected through a third contactor normally closed and actuated for its opening by a delaying relay itself fed through a fourth contactor, whereby said circuit is opened with a delay in its excitation corresponding to the time required for the automatic change of speeds, one by one, and for filling said bottle; a third and a fourth interrupter provided in parallel and between the first two interruptors, said third and fourth interruptors being adaped to be closed by said regulator for two distinct intermediate operating speeds of said first driven shaft; each of said third and fourth interruptors being in series with one of two auxiliary contactors; said auxiliary contactors being combined with said accelerating means in such a manner that the auX- iliary contactor located in the circuit of the relay for the increase is closed when said accelerating means is in the position of total acceleration while the auxiliary contactor located in the circuit of the relay for the decrease is closed when said accelerating means is in released position.

12. The combination as claimed in claim 11, comprising further: on the feed circuit in parallel of said two electro-magnets and of the windings of the relays and in the circuit passing through all interruptors previously identified and actuated by said regulator, a fifth and a sixth interruptor, actuated by a manual element allowing either to cut off all the circuits for a manual operation of said selector, or a hand-controlled electric feed through said reverser, or again an automatic electric feed through said interruptors previously identified.

References Cited in the file of this patent UNITED STATES PATENTS 2,845,819 Laburte Aug. 5, 1958 FOREIGN PATENTS 1,023,681 Germany Jan. 30, 1958 

